If you visited yesterday afternoon and noticed that the site was down, know that it was because I was upgrading the server from Ubuntu 6.06 LTS to Ubuntu 7.10, the latest release (codenamed Gutsy Gibbon, hence the title). You can see a full list of all Ubuntu releases at their wiki.
While I could have continued using Ubuntu 6.10 until its end of life in 2011, I wanted to use newer software that was not available in 6.06 (including exotic VPN options and Python 2.5). The process was more difficult than it should have been, because 6.06 is so old (three versions behind 7.10) and the next LTS release (which I would be able to directly upgrade to, as opposed to upgrading to 6.10 and then 7.04 and then 7.10, each time risking breakage) will not be released until April 2008.
As a result, I ended up backing up all of my data and doing a clean installation. It took me three tries, but only because I started too late in the night and got tired in the middle (leading me to restore the previous configuration from Slicehost's integrated backups), not because I ran into technical issues.
I used phpmyadmin for backing up the data from my MySQL databases, which had the unfortunate effect of ruining the Unicode data (turning entries where I posted quotations in French into gibberish). I think I have fixed it everywhere now, though.
What hosting service do you use? Or do you actually own the server itself (and thus can upgrade at will)?
I have a VPS at Slicehost. All of the headache of owning your own server at low, low cost.
Seriously, owning your own server (even a virtual one) is very liberating, and sometimes even fun.